Misfires and much more

[wizechatmgr]

If you double click on those cylinder misfire codes traffic icons it should have counters if I remember correctly.

These cars are old enough that a code coming up once doesn't worry me. If it keeps appearing then it is worthy of attention.

If you're having misfires you would have known. The car would have bucked and lunged and would generally be similar to riding on a unhappy bull at a rodeo.

Check the grounds on top of the valve cover - I believe those ground the ignition coils and I believe there should be two. Sometimes the wires in this area get pinched and it doesn't become apparent until later on.

You can also test the fuel injectors by unplugging the harness from them. If you get one that doesn't seem to make it idle rough when unplugged it is most likely leaking or full on obstructed. More or less same for your coils. Keep in mind this will likely set codes, so erase them before and after.

I'd ignore the cat code for now. That's likely being set by the misfires.

[scot850]

Try to find the test for the VVT solenoid to check it is operating and try cycling it to make sure it is working.

Neil.

[volvolugnut]

Fuel injectors can be tested off the car with a short hose attached to the input side. Clamp the injector to some metal object with the inlet up. Fill the hose with a little carb cleaner or similar. Attach a transistor 9 volt battery to the injector terminals and quickly make and break the connection at the battery. The injector will open each time you make contact with the power. You should also hear a faint click. If you get no spray or little the injector is dirty. Repeating the process may clean the injector.
Of course, you may have created a flame thrower if there is a spark.
volvolugnut

[Maestrours]

Thanks for all your answers. My vvt solenoid is brand new, as I struggled last year with ecm 644a, 643a. Since i changed it and did a timing it seems to work properly.
I cleaned injectors last year with ultrasound cleaner and changed o rings and filter so i'll act like if they are good for the moment.

As température is cooling now, I checked my fuel sensor and saw that ethanol has not been set on winter mode, with a lot more gasoline than in summer. So i did fill some gasoline in the tank and misfires did not came back...

I'd ignore the cat code for now. That's likely being set by the misfires.

.. But ecm-4801 ( cat converter) did, as it always since I bought this car.
It appeared at low speed, 30mph, no charge, in the traffic. It nevers appears when i'm driving in highway but more when i'm in town.
I bought this car almost in barn state, etm was dead, timing was not set correctly, head gasket was dead. I assume it was driven many years with an awful timing setting. Can it damage the cat conv ? How can I diagnose this with certitude ?

Thanks all !

[Maestrours]

Here are my 02 sensors at idle

IMG_20231115_185123.jpg (402.08 KiB) Viewed 383 times

[scot850]

Probably the only way is to take it to a repair shop that can test your exhaust emissions. The only other things that may control/test the emissions are the O2 sensors. They will or should throw a code if they are bad.

Good news on the other stuff clearing up hopefully now.

Neil.

[wizechatmgr]

Thanks for all your answers. My vvt solenoid is brand new, as I struggled last year with ecm 644a, 643a. Since i changed it and did a timing it seems to work properly.
I cleaned injectors last year with ultrasound cleaner and changed o rings and filter so i'll act like if they are good for the moment.

As température is cooling now, I checked my fuel sensor and saw that ethanol has not been set on winter mode, with a lot more gasoline than in summer. So i did fill some gasoline in the tank and misfires did not came back...

I'd ignore the cat code for now. That's likely being set by the misfires.

.. But ecm-4801 ( cat converter) did, as it always since I bought this car.
It appeared at low speed, 30mph, no charge, in the traffic. It nevers appears when i'm driving in highway but more when i'm in town.
I bought this car almost in barn state, etm was dead, timing was not set correctly, head gasket was dead. I assume it was driven many years with an awful timing setting. Can it damage the cat conv ? How can I diagnose this with certitude ?

Thanks all !

This link goes over catalytic converter meltdown due to running rich (misfires) among other topics
https://www.walkerexhaust.com/support/t ... vy%20load.

[wizechatmgr]

Front O2 sensor seems to be indicating a perfect running engine. The rear tells another story. One of these two is likely wrong. Which? Well, that's the tough one. If I had to guess I'd say the rear but as scot850 said, if you can have someone test the gases from the exhaust that will tell you which is right, and which is wrong.

[wizechatmgr]

How long was the car running when you got these values from the O2 sensors, etc.? If it was at idle and had not been running at say highway or local around town speeds, it could be the front is being set by the computer as a reference voltage until it gets into closed loop mode and that the rear is true since it's a heated sensor.

[Maestrours]

How long was the car running when you got these values from the O2 sensors, etc.? If it was at idle and had not been running at say highway or local around town speeds, it could be the front is being set by the computer as a reference voltage until it gets into closed loop mode and that the rear is true since it's a heated sensor.

The car was juste at starting, idling after 2 3 minutes. I already had driven in traffic jam 1 hour ago.

The problem is I have very limited knowledges about 02 sensor, maybe i'll have to improve this.

Here is the report of Vida at the moment the car threw the 4801 code:

Screenshot_20231117_164009_com.android.gallery3d.jpg (145.56 KiB) Viewed 350 times

Thanks for this help !